scroll_events_test.dart

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter_test/flutter_test.dart';
import 'package:flutter/widgets.dart';
import 'package:test/test.dart';

Widget _buildScroller({Key key, List<String> log}) {
  return new ScrollableViewport(
    key: key,
    onScrollStart: (double scrollOffset) {
      log.add('scrollstart');
    },
    onScroll: (double scrollOffset) {
      log.add('scroll');
    },
    onScrollEnd: (double scrollOffset) {
      log.add('scrollend');
    },
    child: new Container(width: 1000.0, height: 1000.0)
  );
}

void main() {
  test('Scroll event drag', () {
    testWidgets((WidgetTester tester) {
      List<String> log = <String>[];
      tester.pumpWidget(_buildScroller(log: log));

      expect(log, equals([]));
      TestGesture gesture = tester.startGesture(new Point(100.0, 100.0));
      expect(log, equals(['scrollstart']));
      tester.pump(const Duration(seconds: 1));
      expect(log, equals(['scrollstart']));
      gesture.moveBy(new Offset(-10.0, -10.0));
      expect(log, equals(['scrollstart', 'scroll']));
      tester.pump(const Duration(seconds: 1));
      expect(log, equals(['scrollstart', 'scroll']));
      gesture.up();
      expect(log, equals(['scrollstart', 'scroll']));
      tester.pump(const Duration(seconds: 1));
      expect(log, equals(['scrollstart', 'scroll', 'scrollend']));
    });
  });

  test('Scroll scrollTo animation', () {
    testWidgets((WidgetTester tester) {
      GlobalKey<ScrollableState> scrollKey = new GlobalKey<ScrollableState>();
      List<String> log = <String>[];
      tester.pumpWidget(_buildScroller(key: scrollKey, log: log));

      expect(log, equals([]));
      scrollKey.currentState.scrollTo(100.0, duration: const Duration(seconds: 1));
      expect(log, equals(['scrollstart']));
      tester.pump(const Duration(milliseconds: 100));
      expect(log, equals(['scrollstart']));
      tester.pump(const Duration(milliseconds: 100));
      expect(log, equals(['scrollstart', 'scroll']));
      tester.pump(const Duration(milliseconds: 1500));
      expect(log, equals(['scrollstart', 'scroll', 'scroll', 'scrollend']));
    });
  });

  test('Scroll scrollTo no animation', () {
    testWidgets((WidgetTester tester) {
      GlobalKey<ScrollableState> scrollKey = new GlobalKey<ScrollableState>();
      List<String> log = <String>[];
      tester.pumpWidget(_buildScroller(key: scrollKey, log: log));

      expect(log, equals([]));
      scrollKey.currentState.scrollTo(100.0);
      expect(log, equals(['scrollstart', 'scroll', 'scrollend']));
    });
  });

  test('Scroll during animation', () {
    testWidgets((WidgetTester tester) {
      GlobalKey<ScrollableState> scrollKey = new GlobalKey<ScrollableState>();
      List<String> log = <String>[];
      tester.pumpWidget(_buildScroller(key: scrollKey, log: log));

      expect(log, equals([]));
      scrollKey.currentState.scrollTo(100.0, duration: const Duration(seconds: 1));
      expect(log, equals(['scrollstart']));
      tester.pump(const Duration(milliseconds: 100));
      expect(log, equals(['scrollstart']));
      tester.pump(const Duration(milliseconds: 100));
      expect(log, equals(['scrollstart', 'scroll']));
      scrollKey.currentState.scrollTo(100.0);
      expect(log, equals(['scrollstart', 'scroll', 'scroll']));
      tester.pump(const Duration(milliseconds: 100));
      expect(log, equals(['scrollstart', 'scroll', 'scroll', 'scrollend']));
      tester.pump(const Duration(milliseconds: 1500));
      expect(log, equals(['scrollstart', 'scroll', 'scroll', 'scrollend']));
    });
  });

  test('Scroll during animation', () {
    testWidgets((WidgetTester tester) {
      GlobalKey<ScrollableState> scrollKey = new GlobalKey<ScrollableState>();
      List<String> log = <String>[];
      tester.pumpWidget(_buildScroller(key: scrollKey, log: log));

      expect(log, equals([]));
      scrollKey.currentState.scrollTo(100.0, duration: const Duration(seconds: 1));
      expect(log, equals(['scrollstart']));
      tester.pump(const Duration(milliseconds: 100));
      expect(log, equals(['scrollstart']));
      tester.pump(const Duration(milliseconds: 100));
      expect(log, equals(['scrollstart', 'scroll']));
      scrollKey.currentState.scrollTo(100.0, duration: const Duration(seconds: 1));
      expect(log, equals(['scrollstart', 'scroll']));
      tester.pump(const Duration(milliseconds: 100));
      expect(log, equals(['scrollstart', 'scroll']));
      tester.pump(const Duration(milliseconds: 1500));
      expect(log, equals(['scrollstart', 'scroll', 'scroll', 'scrollend']));
    });
  });

  test('fling, fling generates one start/end pair', () {
    testWidgets((WidgetTester tester) {
      GlobalKey<ScrollableState> scrollKey = new GlobalKey<ScrollableState>();
      List<String> log = <String>[];
      tester.pumpWidget(_buildScroller(key: scrollKey, log: log));

      expect(log, equals([]));
      tester.flingFrom(new Point(100.0, 100.0), new Offset(-50.0, -50.0), 500.0);
      tester.pump(new Duration(seconds: 1));
      log.removeWhere((String value) => value == 'scroll');
      expect(log, equals(['scrollstart']));
      tester.flingFrom(new Point(100.0, 100.0), new Offset(-50.0, -50.0), 500.0);
      tester.pump(new Duration(seconds: 1));
      tester.pump(new Duration(seconds: 1));
      log.removeWhere((String value) => value == 'scroll');
      expect(log, equals(['scrollstart', 'scrollend']));
    });
  });
}